This section provides background information related to the present disclosure which is not necessarily prior art. This section also provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features
Global warming is a household phrase today and does not require any additional explanation or discussion. Nations are willing to spend billions to stop global warming at current levels and not worsen the situation. A great focus is on developing unconventional or renewable energy sources. Unmistakably, the Solar and Wind Energy technologies have progressed significantly that a great emphasis is laid on exploiting these sources. Wave and Tidal energy are still in the initial development stages and it is only a few countries in Europe and the USA that are devoting resources to exploit them.
Solar energy is available only during the day time and lack of energy storage devices pose as a significant disadvantage. The sun energy is at the lowest during the daybreak, peaks at noon and wanes to low levels at sunset. During the day, average solar energy supply increases to a peak then decreases and does not remain constant. When solar energy decreases to low levels during the day or when it drops to zero during the night, alternate energy sources must be available to keep up with the demand. Harnessing solar power requires substantial capital and above that additional investment is required to maintain and establish alternate sources to match demand when the sun recedes. Moreover countries farther away from the equator do not qualify as potential candidates.
Likewise, wind energy is seasonal. Even during windy seasons, wind does not remain constant and varies periodically. Similar to Solar Energy, Wind Energy systems also require investment in stand-by sources to keep up with the demand when the winds slow down or drop to insignificant levels.
On the other hand, wave energy, when compared to the other two, is more reliable. Over a wider time period a reasonably unceasing wave power supply can be expected. The energy variations are, however, not as significant as Solar and Wind Energy. But in shorter time intervals (in minutes and seconds) Wave Power fluctuates momentarily. This requires a wave power absorption and conversion system that can store momentary peak power and release for supplementation during momentary periods of low power. The Wave Power industry today stores this momentary excess energy in a battery as electrical energy or in a pressure vessel as pressure energy. The stored energy is utilized within short periods of time (minutes or seconds) and do not necessitate long term (in hours or days) storage. The present wave energy conversion devices either directly run an electric generator that stores electric energy in battery banks or operates a hydraulic motor that stores pressure energy in pressure vessels. The stored pressure is then released at a constant rate to run a hydraulic turbine/motor coupled to an electric generator.
A problem faced by the Wave Power Industry is sudden strikes by higher intensity waves. During a given time period, kinetic forces associated with each wave is predominantly constant. However, it is not uncommon to observe a wave break with very less force or on the contrary one with much higher magnitude of force. This requires the Wave Energy Absorption and Conversion system to be adequately designed for waves with the higher magnitude to avoid structural failures.
In conventional systems or apparatus that absorb and convert wave energy, only one or two of the ocean movements (pitch, sway, yaw, surge, roll and heave) are absorbed or converted (see FIGS. 1B and 1C). The forces associated with the other remaining motions are not absorbed and hence the apparatus is required to structurally withstand these forces. As these non-absorbed forces strike from different directions the apparatus requires considerable strengthening in all dimensions to withstand the resultant stresses. To increase the strength material selection and higher yield strengths will help to an extent. Beyond which the size will require an increase. Increased size will expose more surface area to the ocean movement that result in higher forces and thus the designer faces a vicious circle. Ultimately a bulky, heavy, hard to handle, expensive structure is required to absorb and convert relatively low power.
In reality, a free floating device made of resilient material left on the ocean water surface that is not tied up, fixed, or moored will float, pitch, sway, yaw, surge, roll, and heave with the waves. The stress experienced by this device is not significant and is mainly due to its own weight and geometry. Let this floating device be attached to a structural member (a beam, shaft, arm, etc.) to actuate a device (electric generator or pressure pump) to absorb or convert the energy transferred to the floating device by the waves. If the member is allowed freedom of motion only in the “Y” direction to absorb heave motion, then when other motions like sway, pitch, surge, etc. accompany the heave motion this member has to perform two functions—one to convey the heave motion to the device for absorption and conversion of the heave forces and other to hold the floating device in place by withstanding the unused forces caused by motions associated with sway, pitch, surge etc. This results in other complex forces like bending, shear, torsion etc. that this member has to withstand.
This disadvantage is eliminated or reduced significantly by the system of the present teachings, which is capable of absorbing forces associated with all ocean motions, including pitch, sway, yaw, surge, roll, and heave. The forces generated on the system will be equal to resistance offered by the hydraulic pump or the electrical generator.
Additionally, all these multi-directional forces are absorbed and focused into a one directional rotational motion. This eliminates the requirement to design the structure for all types of multi directional forces. The structure will experience forces equal to resistance offered by the hydraulic pump or the electrical generator. The principle component of this system will be the gear box which will be designed to absorb all types of forces associated with all motions of the ocean. The maximum forces applied on the gear box will only equal to the resistance offered by the hydraulic pump or the electrical generator. The primary function of the structure is only to support the gear box.
The gear box can be scaled up or down based on the power requirement dictated by the specifications of the selected electrical generator or hydraulic motor. The size and strength of the structure will be designed simply to support the gear box.
Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.